Separate CodeAssembler and CodeStubAssembler

src/compiler/code-assembler.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef V8_COMPILER_CODE_STUB_ASSEMBLER_H_
-#define V8_COMPILER_CODE_STUB_ASSEMBLER_H_
+#ifndef V8_COMPILER_CODE_ASSEMBLER_H_
+#define V8_COMPILER_CODE_ASSEMBLER_H_
 
 #include <map>
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/allocation.h"
 #include "src/builtins.h"
 #include "src/heap/heap.h"
 #include "src/machine-type.h"
 #include "src/runtime/runtime.h"
@@ skipping 79 matching lines @@
   V(Word64Or)                                   \
   V(Word64And)                                  \
   V(Word64Xor)                                  \
   V(Word64Shr)                                  \
   V(Word64Sar)                                  \
   V(Word64Ror)
 
 #define CODE_STUB_ASSEMBLER_UNARY_OP_LIST(V) \
   V(Float64Neg)                              \
   V(Float64Sqrt)                             \
+  V(Float64ExtractLowWord32)                 \
+  V(Float64ExtractHighWord32)                \
+  V(TruncateInt64ToInt32)                    \
   V(ChangeFloat64ToUint32)                   \
   V(ChangeInt32ToFloat64)                    \
   V(ChangeInt32ToInt64)                      \
   V(ChangeUint32ToFloat64)                   \
   V(ChangeUint32ToUint64)                    \
   V(Word32Clz)
 
-class CodeStubAssembler {
+// A "public" interface used by components outside of compiler directory to
+// create code objects with TurboFan's backend. This class is mostly a thin shim
+// around the RawMachineAssembler, and its primary job is to ensure that the
+// innards of the RawMachineAssembler and other compiler implementation details
+// don't leak outside of the the compiler directory..
+//
+// V8 components that need to generate low-level code using this interface
+// should include this header--and this header only--from the compiler directory
+// (this is actually enforced). Since all interesting data structures are
+// forward declared, it's not possible for clients to peek inside the compiler
+// internals.
+//
+// In addition to providing isolation between TurboFan and code generation
+// clients, CodeAssembler also provides an abstraction for creating variables
+// and enhanced Label functionality to merge variable values along paths where
+// they have differing values, including loops.
+class CodeAssembler {
  public:
   // Create with CallStub linkage.
   // |result_size| specifies the number of results returned by the stub.
   // TODO(rmcilroy): move result_size to the CallInterfaceDescriptor.
-  CodeStubAssembler(Isolate* isolate, Zone* zone,
-                    const CallInterfaceDescriptor& descriptor,
-                    Code::Flags flags, const char* name,
-                    size_t result_size = 1);
+  CodeAssembler(Isolate* isolate, Zone* zone,
+                const CallInterfaceDescriptor& descriptor, Code::Flags flags,
+                const char* name, size_t result_size = 1);
 
   // Create with JSCall linkage.
-  CodeStubAssembler(Isolate* isolate, Zone* zone, int parameter_count,
-                    Code::Flags flags, const char* name);
+  CodeAssembler(Isolate* isolate, Zone* zone, int parameter_count,
+                Code::Flags flags, const char* name);
 
-  virtual ~CodeStubAssembler();
+  virtual ~CodeAssembler();
 
   Handle<Code> GenerateCode();
 
+  bool Is64();

[Benedikt Meurer, 2016/04/11 18:12:09]

Nit: const

[danno, 2016/04/18 11:00:04]

Done.

+
   class Label;
   class Variable {
    public:
-    explicit Variable(CodeStubAssembler* assembler, MachineRepresentation rep);
+    explicit Variable(CodeAssembler* assembler, MachineRepresentation rep);
     void Bind(Node* value);
     Node* value() const;
     MachineRepresentation rep() const;
     bool IsBound() const;
 
    private:
-    friend class CodeStubAssembler;
+    friend class CodeAssembler;
     class Impl;
     Impl* impl_;
   };
 
   enum AllocationFlag : uint8_t {
     kNone = 0,
     kDoubleAlignment = 1,
     kPretenured = 1 << 1
   };
 
@@ skipping 52 matching lines @@
   CODE_STUB_ASSEMBLER_BINARY_OP_LIST(DECLARE_CODE_STUB_ASSEMBER_BINARY_OP)
 #undef DECLARE_CODE_STUB_ASSEMBER_BINARY_OP
 
   Node* WordShl(Node* value, int shift);
 
 // Unary
 #define DECLARE_CODE_STUB_ASSEMBER_UNARY_OP(name) Node* name(Node* a);
   CODE_STUB_ASSEMBLER_UNARY_OP_LIST(DECLARE_CODE_STUB_ASSEMBER_UNARY_OP)
 #undef DECLARE_CODE_STUB_ASSEMBER_UNARY_OP
 
+  Node* TruncateFloat64ToInt32RoundToZero(Node* a);
+  Node* TruncateFloat64ToInt32JavaScript(Node* a);
+
   // Projections
   Node* Projection(int index, Node* value);
 
   // Calls
   Node* CallRuntime(Runtime::FunctionId function_id, Node* context);
   Node* CallRuntime(Runtime::FunctionId function_id, Node* context, Node* arg1);
   Node* CallRuntime(Runtime::FunctionId function_id, Node* context, Node* arg1,
                     Node* arg2);
   Node* CallRuntime(Runtime::FunctionId function_id, Node* context, Node* arg1,
                     Node* arg2, Node* arg3);
@@ skipping 40 matching lines @@
                      Node* context, Node* arg1, Node* arg2,
                      size_t result_size = 1);
 
   Node* TailCall(const CallInterfaceDescriptor& descriptor, Node* target,
                  Node** args, size_t result_size = 1);
 
   // ===========================================================================
   // Macros
   // ===========================================================================
 
+  // Tag a Word as a Smi value.
+  Node* SmiTag(Node* value);
+  // Untag a Smi value as a Word.
+  Node* SmiUntag(Node* value);
+
   // Float64 operations.
   Node* Float64Ceil(Node* x);
   Node* Float64Floor(Node* x);
   Node* Float64Round(Node* x);
   Node* Float64Trunc(Node* x);
 
-  // Tag a Word as a Smi value.

[Benedikt Meurer, 2016/04/11 18:12:09]

I think those Smi helpers should be in the CodeAssembler too, esp. since we have
SmiTag/SmiUntag there as well.

[danno, 2016/04/18 11:00:03]

As discussed, I see them there too, but I can't move them until we move the
allocation wrappers out, too, and that's more work because they use the
RawMachineAssembler directly. I'll address that separately.

-  Node* SmiTag(Node* value);
-  // Untag a Smi value as a Word.
-  Node* SmiUntag(Node* value);
-
-  // Smi conversions.
-  Node* SmiToFloat64(Node* value);
-  Node* SmiToWord32(Node* value);
-
-  // Smi operations.
-  Node* SmiAdd(Node* a, Node* b);
-  Node* SmiAddWithOverflow(Node* a, Node* b);
-  Node* SmiSub(Node* a, Node* b);
-  Node* SmiSubWithOverflow(Node* a, Node* b);
-  Node* SmiEqual(Node* a, Node* b);
-  Node* SmiLessThan(Node* a, Node* b);
-  Node* SmiLessThanOrEqual(Node* a, Node* b);
-  Node* SmiMin(Node* a, Node* b);
-
   // Load a value from the root array.
   Node* LoadRoot(Heap::RootListIndex root_index);
 
-  // Check a value for smi-ness
-  Node* WordIsSmi(Node* a);
-
-  // Check that the value is a positive smi.
-  Node* WordIsPositiveSmi(Node* a);
-
-  // Load an object pointer from a buffer that isn't in the heap.
-  Node* LoadBufferObject(Node* buffer, int offset,
-                         MachineType rep = MachineType::AnyTagged());
-  // Load a field from an object on the heap.
-  Node* LoadObjectField(Node* object, int offset,
-                        MachineType rep = MachineType::AnyTagged());
-  // Load the floating point value of a HeapNumber.
-  Node* LoadHeapNumberValue(Node* object);
-  // Store the floating point value of a HeapNumber.
-  Node* StoreHeapNumberValue(Node* object, Node* value);
-  // Truncate the floating point value of a HeapNumber to an Int32.
-  Node* TruncateHeapNumberValueToWord32(Node* object);
-  // Load the bit field of a Map.
-  Node* LoadMapBitField(Node* map);
-  // Load bit field 2 of a map.
-  Node* LoadMapBitField2(Node* map);
-  // Load bit field 3 of a map.
-  Node* LoadMapBitField3(Node* map);
-  // Load the instance type of a map.
-  Node* LoadMapInstanceType(Node* map);
-  // Load the instance descriptors of a map.
-  Node* LoadMapDescriptors(Node* map);
-
-  // Load the hash field of a name.
-  Node* LoadNameHash(Node* name);
-
-  // Load an array element from a FixedArray.
-  Node* LoadFixedArrayElementInt32Index(Node* object, Node* int32_index,
-                                        int additional_offset = 0);
-  Node* LoadFixedArrayElementSmiIndex(Node* object, Node* smi_index,
-                                      int additional_offset = 0);
-  Node* LoadFixedArrayElementConstantIndex(Node* object, int index);
-
   // Allocate an object of the given size.
   Node* Allocate(int size, AllocationFlags flags = kNone);
-  // Allocate a HeapNumber without initializing its value.
-  Node* AllocateHeapNumber();
-  // Allocate a HeapNumber with a specific value.
-  Node* AllocateHeapNumberWithValue(Node* value);
-
-  // Store an array element to a FixedArray.
-  Node* StoreFixedArrayElementNoWriteBarrier(Node* object, Node* index,
-                                             Node* value);
-  // Load the Map of an HeapObject.
-  Node* LoadMap(Node* object);
-  // Store the Map of an HeapObject.
-  Node* StoreMapNoWriteBarrier(Node* object, Node* map);
-  // Load the instance type of an HeapObject.
-  Node* LoadInstanceType(Node* object);
-
-  // Load the elements backing store of a JSObject.
-  Node* LoadElements(Node* object);
-  // Load the length of a fixed array base instance.
-  Node* LoadFixedArrayBaseLength(Node* array);
-
-  // Returns a node that is true if the given bit is set in |word32|.
-  template <typename T>
-  Node* BitFieldDecode(Node* word32) {
-    return BitFieldDecode(word32, T::kShift, T::kMask);
-  }
-
-  Node* BitFieldDecode(Node* word32, uint32_t shift, uint32_t mask);
-
-  // Conversions.
-  Node* ChangeFloat64ToTagged(Node* value);
-  Node* ChangeInt32ToTagged(Node* value);
-  Node* TruncateTaggedToFloat64(Node* context, Node* value);
-  Node* TruncateTaggedToWord32(Node* context, Node* value);
 
   // Branching helpers.
-  // TODO(danno): Can we be more cleverish wrt. edge-split?
   void BranchIf(Node* condition, Label* if_true, Label* if_false);
 
 #define BRANCH_HELPER(name)                                                \
   void BranchIf##name(Node* a, Node* b, Label* if_true, Label* if_false) { \
     BranchIf(name(a, b), if_true, if_false);                               \
   }
   CODE_STUB_ASSEMBLER_COMPARE_BINARY_OP_LIST(BRANCH_HELPER)
 #undef BRANCH_HELPER
 
-  void BranchIfSmiLessThan(Node* a, Node* b, Label* if_true, Label* if_false) {
-    BranchIf(SmiLessThan(a, b), if_true, if_false);
-  }
-
-  void BranchIfSmiLessThanOrEqual(Node* a, Node* b, Label* if_true,
-                                  Label* if_false) {
-    BranchIf(SmiLessThanOrEqual(a, b), if_true, if_false);
-  }
-
   void BranchIfFloat64IsNaN(Node* value, Label* if_true, Label* if_false) {
     BranchIfFloat64Equal(value, value, if_false, if_true);
   }
 
   // Helpers which delegate to RawMachineAssembler.
   Factory* factory() const;
   Isolate* isolate() const;
   Zone* zone() const;
 
  protected:
   // Protected helpers which delegate to RawMachineAssembler.
   Graph* graph() const;
 
   // Enables subclasses to perform operations before and after a call.
   virtual void CallPrologue();
   virtual void CallEpilogue();
 
+  Node* SmiShiftBitsConstant();
+
  private:
-  friend class CodeStubAssemblerTester;
+  friend class CodeAssemblerTester;
 
-  CodeStubAssembler(Isolate* isolate, Zone* zone,
-                    CallDescriptor* call_descriptor, Code::Flags flags,
-                    const char* name);
+  CodeAssembler(Isolate* isolate, Zone* zone, CallDescriptor* call_descriptor,
+                Code::Flags flags, const char* name);
 
   Node* CallN(CallDescriptor* descriptor, Node* code_target, Node** args);
   Node* TailCallN(CallDescriptor* descriptor, Node* code_target, Node** args);
 
-  Node* SmiShiftBitsConstant();
-
   Node* AllocateRawAligned(Node* size_in_bytes, AllocationFlags flags,
                            Node* top_address, Node* limit_address);
   Node* AllocateRawUnaligned(Node* size_in_bytes, AllocationFlags flags,
                              Node* top_adddress, Node* limit_address);
 
   base::SmartPointer<RawMachineAssembler> raw_assembler_;
   Code::Flags flags_;
   const char* name_;
   bool code_generated_;
   ZoneVector<Variable::Impl*> variables_;
 
-  DISALLOW_COPY_AND_ASSIGN(CodeStubAssembler);
+  DISALLOW_COPY_AND_ASSIGN(CodeAssembler);
 };
 
-DEFINE_OPERATORS_FOR_FLAGS(CodeStubAssembler::AllocationFlags);
+DEFINE_OPERATORS_FOR_FLAGS(CodeAssembler::AllocationFlags);
 
-class CodeStubAssembler::Label {
+class CodeAssembler::Label {
  public:
   enum Type { kDeferred, kNonDeferred };
 
-  explicit Label(CodeStubAssembler* assembler,
-                 CodeStubAssembler::Label::Type type =
-                     CodeStubAssembler::Label::kNonDeferred)
-      : CodeStubAssembler::Label(assembler, 0, nullptr, type) {}
-  Label(CodeStubAssembler* assembler,
-        CodeStubAssembler::Variable* merged_variable,
-        CodeStubAssembler::Label::Type type =
-            CodeStubAssembler::Label::kNonDeferred)
-      : CodeStubAssembler::Label(assembler, 1, &merged_variable, type) {}
-  Label(CodeStubAssembler* assembler, int merged_variable_count,
-        CodeStubAssembler::Variable** merged_variables,
-        CodeStubAssembler::Label::Type type =
-            CodeStubAssembler::Label::kNonDeferred);
+  explicit Label(
+      CodeAssembler* assembler,
+      CodeAssembler::Label::Type type = CodeAssembler::Label::kNonDeferred)
+      : CodeAssembler::Label(assembler, 0, nullptr, type) {}
+  Label(CodeAssembler* assembler, CodeAssembler::Variable* merged_variable,
+        CodeAssembler::Label::Type type = CodeAssembler::Label::kNonDeferred)
+      : CodeAssembler::Label(assembler, 1, &merged_variable, type) {}
+  Label(CodeAssembler* assembler, int merged_variable_count,
+        CodeAssembler::Variable** merged_variables,
+        CodeAssembler::Label::Type type = CodeAssembler::Label::kNonDeferred);
   ~Label() {}
 
  private:
-  friend class CodeStubAssembler;
+  friend class CodeAssembler;
 
   void Bind();
   void MergeVariables();
 
   bool bound_;
   size_t merge_count_;
-  CodeStubAssembler* assembler_;
+  CodeAssembler* assembler_;
   RawMachineLabel* label_;
   // Map of variables that need to be merged to their phi nodes (or placeholders
   // for those phis).
   std::map<Variable::Impl*, Node*> variable_phis_;
   // Map of variables to the list of value nodes that have been added from each
   // merge path in their order of merging.
   std::map<Variable::Impl*, std::vector<Node*>> variable_merges_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
-#endif  // V8_COMPILER_CODE_STUB_ASSEMBLER_H_
+#endif  // V8_COMPILER_CODE_ASSEMBLER_H_